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efA. FREAR.

Precess and Implements fer Expelling Air from the Cempositio-n from which Artificial Stone is Molded.

N0. 137,193. PatentedMarch25,l873.

UNITED STATES PATENT OFFICE.

GEORGE A. FREAR, or CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF HIS I RIGHT TO CHARLES HOLLAND, OF SAME PLACE.

IMPROVEMENT IN PROCESSES AND IMPLEMENTS FOR EXPELLING AIR FROM THE COMPOSITION FROM WHICH ARTIFICIAL STONE IS MOLDED.

Specification forming part of Letters Patent No. 137,193, dated March 25, 1873.

To all whom it may concern:

Be it known that I, GEORGE A. FREAK, of Chicago, in the county of Cook and State of Illinois, have invented an Improved Process and Implement for Expelling Air from the Composition from which Artificial Stone is Molded, of which the following is a specification:

In molding artificial marble or other artificial stone from any plastic mass or composition, it becomes important to expel the air which will be held in small globules throughout the mass. This may be done imperfectly by violently jolting the mold, or striking it with a mallet or hammer, or by tamping in the material; but, in addition to the difficulty of completely expelling the air by such means, the mass will be left full of small irregular airholes within and on the surface, which it will be found impossible to close, at least without excessive tamping, inasmuch as the air cannot all be expelled quickly by such means. The porosity thus produced not only tends to weaken the stone, and to render it pervious to water and other liquids, but renders it necessary to fill up the holes in the surface, especially if the stone is to be polished.

To obviate these defects I perforate the mass in the mold very numerously by means of needles or small wires, or other sharppointed instruments, and then partially expel the air by violently jolting the mold by lifting and letting it fall on the table or floor, or by striking it with a mallet or hammer on its back part. The perforations should be made near together so as to puncture as many as practicable of the air globules in the mass. The jolting or pounding of the mold, as described, tends to close the perforations at their lower extremities, first, so as to expel the air contained in said perforations as they are closed up. After the air is thus partially expelled,

the mass may be further compacted by press ure or by tamping.

In the accompanying drawing, three instruments are shown for perforating the mass in the mold.

Figure 1 represents a rotary perforator, con sisting of a small wheel armed with numerous radiall y-projectin g needles or wires, and which is used to run around the edge of the mold where there is an ogee or other nolding. Fig. 2represents a rotary perforator operating on the same principle, the needles radiating from a long revolving shaft instead of a narrow wheel, as shown in Fig. 1. Figs. 3 and 3a represent an instrument which consists of a board or plate with numerous needles or wires projecting from its lower side at right angles to the plate-3 being a side view, and 3a a face view.

This instrument is used by pressing it down vertically until its needles or wires completely penetrate themass, and then withdrawing it. It may be varied in size according to the mass to be operated upon. For large slabs, such as table and bureau tops, it may be a foot square.

Figs. 2 and 3 both represent instruments to be used on plain surfaces. 1

What I claim as my invention, and desire to secure by Letters Patent, is

1. The process herein described of expelling the air from the plastic mass from which artificial stone is molded, by perforating the mass in the mold with numerous small holes, and jolting or striking the mold or tamping the mass, substantially as described.

2. The instruments represented in Figs. 1, 2, and 3, substantially as and for the purpose described.

Witnesses: GEO. A. FREAK.

CALVIN DE WOLF, P. H. Wrrr. 

